Field of the Invention
Exemplary embodiments of the present invention relate to a power train applied to a hybrid vehicle.
Description of Related Art
A hybrid vehicle is a vehicle driven by combining power of an electric motor and power of an internal combustion engine. The hybrid vehicle has been commercially used as an alternative of an eco-friendly vehicle since the hybrid vehicle is operated and controlled by the engine and the electric motor at a mode in which a system has high efficiency, to thereby have high efficiency and effectively reduce exhaust gas.
Such a hybrid vehicle has a power split system configured of a mechanical flow in which power of the engine is directly transferred to an output shaft using a power split device such as a planetary gear for splitting power, and an electric flow in which a generator generates electric power using the power of the engine and a battery is charged using the generated electric power or the motor is driven by energy of the charged battery.
The power split type hybrid system has advantages in that the engine may be operated independently of the output shaft and be freely turned on/off during traveling, and an electric vehicle mode may be realized.
In addition, in the power split type hybrid system, the engine may be effectively driven by an EVT (Electrically Variable Transmission) using two motor generators and a transmission is basically unnecessary since the motor has torque which is uniformly output according to the speed thereof.
However, the transmission is required in order for the vehicle to have high speed and low torque.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.